https://isometrik.itch.io/wave-z

Wave Z is an endless, wave-based zombie game with a simple goal; survive.

It's a heavily modified version of the Survival Shooter Unity tutorial which can be found here (https://unity3d.com/learn/tutorials/s/survival-shooter-tutorial) You might say it's a fan game based on Call of Duty: Black Ops Zombies. What's different about Wave Z not found in the tutorial?

[Windows/Mac/Linux] [still in development] [100% free]

• Weapon upgrade system.
• Perk system.
• Procedural generated (endless) waves of zombies. (The tutorial is just a single wave of endless zombies, rather than having concurrent waves of enemies that gradually increase).
• Custom AI system. 
• Custom animations.
• Custom menu system.
• Custom health and enemy-independent damage systems.
• other additional features not yet in the public build.